A Co-Host is an optional role that the Host can assign to someone (like TA) to assist the Host to mange a meeting. A Co-Host can use most of the Host Controls including Admit attendees, Remove participant, Rename, Mute, Unmute, Mute on Entry, Screen share, Stop Video, Record and some others. During a meeting, Hosts can promote a participant to the role of Co-Host in the Participants tab. To do so:
Click on Participants in the meeting controls at the bottom of the Zoom window.
Hover over the name of the participant who is going to be a co-host, and choose More.
Click Make Co-Host.
You can add as many Co-Hosts in a meeting as you would like.